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Commit | Line | Data |
---|---|---|
00e5a55c BS |
1 | From: Gerald Schaefer <geraldsc@de.ibm.com> |
2 | Subject: kernel: use mutex for appldata_ops instead of spin_lock. | |
3 | References: bnc#487755,LTC#52788 | |
4 | ||
5 | Symptom: Possible deadlock when appldata_mem is active | |
6 | Problem: The appldata_ops callbacks are called with a spin_lock held. | |
7 | But the appldata_mem callback then calls all_vm_events(), which | |
8 | calls get_online_cpus(), which might sleep. | |
9 | Solution: Use a mutex instead of a spin_lock. | |
10 | ||
11 | Acked-by: John Jolly <jjolly@suse.de> | |
12 | --- | |
13 | arch/s390/appldata/appldata_base.c | 32 ++++++++++++++++---------------- | |
14 | arch/s390/appldata/appldata_mem.c | 4 +--- | |
15 | 2 files changed, 17 insertions(+), 19 deletions(-) | |
16 | ||
17 | Index: linux-sles11/arch/s390/appldata/appldata_base.c | |
18 | =================================================================== | |
19 | --- linux-sles11.orig/arch/s390/appldata/appldata_base.c | |
20 | +++ linux-sles11/arch/s390/appldata/appldata_base.c | |
21 | @@ -97,7 +97,7 @@ static DECLARE_WORK(appldata_work, appld | |
22 | /* | |
23 | * Ops list | |
24 | */ | |
25 | -static DEFINE_SPINLOCK(appldata_ops_lock); | |
26 | +static DEFINE_MUTEX(appldata_ops_mutex); | |
27 | static LIST_HEAD(appldata_ops_list); | |
28 | ||
29 | ||
30 | @@ -128,14 +128,14 @@ static void appldata_work_fn(struct work | |
31 | ||
32 | i = 0; | |
33 | get_online_cpus(); | |
34 | - spin_lock(&appldata_ops_lock); | |
35 | + mutex_lock(&appldata_ops_mutex); | |
36 | list_for_each(lh, &appldata_ops_list) { | |
37 | ops = list_entry(lh, struct appldata_ops, list); | |
38 | if (ops->active == 1) { | |
39 | ops->callback(ops->data); | |
40 | } | |
41 | } | |
42 | - spin_unlock(&appldata_ops_lock); | |
43 | + mutex_unlock(&appldata_ops_mutex); | |
44 | put_online_cpus(); | |
45 | } | |
46 | ||
47 | @@ -337,7 +337,7 @@ appldata_generic_handler(ctl_table *ctl, | |
48 | struct list_head *lh; | |
49 | ||
50 | found = 0; | |
51 | - spin_lock(&appldata_ops_lock); | |
52 | + mutex_lock(&appldata_ops_mutex); | |
53 | list_for_each(lh, &appldata_ops_list) { | |
54 | tmp_ops = list_entry(lh, struct appldata_ops, list); | |
55 | if (&tmp_ops->ctl_table[2] == ctl) { | |
56 | @@ -345,15 +345,15 @@ appldata_generic_handler(ctl_table *ctl, | |
57 | } | |
58 | } | |
59 | if (!found) { | |
60 | - spin_unlock(&appldata_ops_lock); | |
61 | + mutex_unlock(&appldata_ops_mutex); | |
62 | return -ENODEV; | |
63 | } | |
64 | ops = ctl->data; | |
65 | if (!try_module_get(ops->owner)) { // protect this function | |
66 | - spin_unlock(&appldata_ops_lock); | |
67 | + mutex_unlock(&appldata_ops_mutex); | |
68 | return -ENODEV; | |
69 | } | |
70 | - spin_unlock(&appldata_ops_lock); | |
71 | + mutex_unlock(&appldata_ops_mutex); | |
72 | ||
73 | if (!*lenp || *ppos) { | |
74 | *lenp = 0; | |
75 | @@ -377,11 +377,11 @@ appldata_generic_handler(ctl_table *ctl, | |
76 | return -EFAULT; | |
77 | } | |
78 | ||
79 | - spin_lock(&appldata_ops_lock); | |
80 | + mutex_lock(&appldata_ops_mutex); | |
81 | if ((buf[0] == '1') && (ops->active == 0)) { | |
82 | // protect work queue callback | |
83 | if (!try_module_get(ops->owner)) { | |
84 | - spin_unlock(&appldata_ops_lock); | |
85 | + mutex_unlock(&appldata_ops_mutex); | |
86 | module_put(ops->owner); | |
87 | return -ENODEV; | |
88 | } | |
89 | @@ -406,7 +406,7 @@ appldata_generic_handler(ctl_table *ctl, | |
90 | "failed with rc=%d\n", ops->name, rc); | |
91 | module_put(ops->owner); | |
92 | } | |
93 | - spin_unlock(&appldata_ops_lock); | |
94 | + mutex_unlock(&appldata_ops_mutex); | |
95 | out: | |
96 | *lenp = len; | |
97 | *ppos += len; | |
98 | @@ -432,9 +432,9 @@ int appldata_register_ops(struct appldat | |
99 | if (!ops->ctl_table) | |
100 | return -ENOMEM; | |
101 | ||
102 | - spin_lock(&appldata_ops_lock); | |
103 | + mutex_lock(&appldata_ops_mutex); | |
104 | list_add(&ops->list, &appldata_ops_list); | |
105 | - spin_unlock(&appldata_ops_lock); | |
106 | + mutex_unlock(&appldata_ops_mutex); | |
107 | ||
108 | ops->ctl_table[0].procname = appldata_proc_name; | |
109 | ops->ctl_table[0].maxlen = 0; | |
110 | @@ -451,9 +451,9 @@ int appldata_register_ops(struct appldat | |
111 | goto out; | |
112 | return 0; | |
113 | out: | |
114 | - spin_lock(&appldata_ops_lock); | |
115 | + mutex_lock(&appldata_ops_mutex); | |
116 | list_del(&ops->list); | |
117 | - spin_unlock(&appldata_ops_lock); | |
118 | + mutex_unlock(&appldata_ops_mutex); | |
119 | kfree(ops->ctl_table); | |
120 | return -ENOMEM; | |
121 | } | |
122 | @@ -465,9 +465,9 @@ out: | |
123 | */ | |
124 | void appldata_unregister_ops(struct appldata_ops *ops) | |
125 | { | |
126 | - spin_lock(&appldata_ops_lock); | |
127 | + mutex_lock(&appldata_ops_mutex); | |
128 | list_del(&ops->list); | |
129 | - spin_unlock(&appldata_ops_lock); | |
130 | + mutex_unlock(&appldata_ops_mutex); | |
131 | unregister_sysctl_table(ops->sysctl_header); | |
132 | kfree(ops->ctl_table); | |
133 | } | |
134 | Index: linux-sles11/arch/s390/appldata/appldata_mem.c | |
135 | =================================================================== | |
136 | --- linux-sles11.orig/arch/s390/appldata/appldata_mem.c | |
137 | +++ linux-sles11/arch/s390/appldata/appldata_mem.c | |
138 | @@ -78,7 +78,7 @@ static void appldata_get_mem_data(void * | |
139 | { | |
140 | /* | |
141 | * don't put large structures on the stack, we are | |
142 | - * serialized through the appldata_ops_lock and can use static | |
143 | + * serialized through the appldata_ops_mutex and can use static | |
144 | */ | |
145 | static struct sysinfo val; | |
146 | unsigned long ev[NR_VM_EVENT_ITEMS]; |